1. Field of the invention
This invention relates to a styrene polymer molding material and a process for producing the same, and more particularly it relates to a styrene polymer molding material which is available as an industrial materials providing excellent heat resistance and a process for producing the same with good efficiency.
2. Description of Related Arts
Styrene polymers which have heretofore been conventionally used were obtained by radical polymerization and have an atactic configuration in their stereoregularity and also are amorphous. These polystyrenes having an atactic configuration have been put to various uses. However, their heat resistance is low and solvent resistance is poor. Therefore, it has been desired to improve their physical properties.
The group of the present inventors, previously developed a styrene polymer having a high degree of syndiotacticity which is expected to be utilized for various uses because it has relatively high crystallinity and a high melting point as compared with conventional atactic polystyrenes, and has excellent heat resistance and solvent resistance. In particular, utilization for an electrical insulating material is expected to be promising. However, the conventional syndiotactic polystyrenes have a melting point of not more than 270.degree. C. so that those which can be directly contacted with high temperature solder are difficult to prepare, even when specific treatments such as thermal resistance treatments are applied (Japanese Patent Application Laid-Open Nos. 244257/1986 and 182348/1989).
Thus, the group of the present inventors has proposed various treatment methods such as electron beam treatment (Japanese Patent Application Laid-Open No. 34647/1990), and solvent treatment (Japanese Patent Application Laid-Open No. 64141/1990), but in order to use the above methods industrially, new instrument are required.